Manufacture of complex structures of sheet material



March 13, 1956 A. VINES ETAL 2,737,725

MANUFACTURE OF COMPLEX STRUCTURES OF SHEET MATERIAL Original Filed April3, 1950 l0 Sheets-Sheet 1 //7 VB for-.5

March 13, 1956 A. VINES ETAL 2,737,725

MANUFACTURE OF COMPLEX STRUCTURES QFSHEET MATERIAL Original Filed April5, 1950 o Sheets-Sheet 2 4 QMRQ 4 Home) March 13,, 1956 A. VlNES ETALMANUFACTURE OF COMPLEX STRUCTURES OF SHEET MATERIAL 1o Sheets-Sheet 5Original Filed Ap ril :5, 1956" a 7 gm? 2M; 5%? 4% MW. 4 m

W W M Mm .NM MM \0 00 0 ON JYQQMQM-RQ March 13, 1956 r A. VlNES ETALMANUFACTURE OF COMPLEX STRUCTURES OF SHEET MATERIAL Original Filed A riis, 1950 0 Sheets-Sheet 4 oa uu u 5 lnven IZarzs Qua Q 10 Sheets-Sheet 5RQQM A. VlNES ETAL /I V/Ifars March 13, 1956 MANUFACTURE OF COMPLEXSTRUCTURES OF SHEET MATERIAL Original Filed April 3, 1950 March 13, 1956A. VINES ETAL 2,737,725

MANUFACTURE OF COMPLEX STRUCTURES OF SHEET-MATERIAL l0 Sheets-Sheet 6Original Filed April 3, 1950 hirer/fans March 13, 1956 A. VINES ETAL2,737,725

MANUFACTURE OF COMPLEX STRUCTURES OF SHEET MATERIAL Original Filed April3, 1950 10 Sheets-Sheet 7 i'fforney March 13, 19756 A. VINES ETAL2,737,725

MANUFACTURE OF COMPLEX STRUCTURES OF SHEET MATERIAL.

10 Sheets-Sheet 8 Original Filed April 3, 1950 March 13, 1956 A. VlNESETAL 2,737,725

MANUFACTUkE OF COMPLEX STRUCTURES OF SHEET MATERIAL Original Filed April5, 1950 10 Sheets-Sheet 9 March 13, 1956 A. VINES ETAL 2,737,725

MANUFACTURE OF COMPLEX STRUCTURES OF SHEET MATERIAL l0 Sheets-Sheet 10Original Filed April 3, 1950 United States Patent MANUFACTURE OF COMPLEXSTRUCTURES OF SHEET MATERIAL Alan Vines, Richmond, Geoffrey LeonardFreeman Welham, Mount Pleasant, South Ruislip, and George ThomasMaughan, Hayes, England, assignors to The iiviation Company Limited,Hayes, Middlesex,

Original application April 3, 1950, Serial No. 153,672. Divided and thisapplication October 15, 1951, Serial No. 256,632 a, I

Claims. (Cl. 33-474) an aircraft wing having a metal skin extending overribs and one or more spars and secured thereto by riveting, the markingout and preparation of the metal skin prior to assembly, known aslofting, is a matter of considerable difliculty owing to the curvaturerequired of the metal skin when it is assembled on the wing ribs andspars. If the skin is marked out when it is flat, the template or othermeans employed as a guide must have been calculated to allow for thesubsequent curvature of the wing surface, so that the wing skin, whencurved, registers correctly with the ribs and spars. This difliculty isincreased when diagonal or other than fore-and'aft ribs are present, andwhen frames or other irregularities are introduced for the accommodationof tanks, landing wheels, and other components. Furthermore, it isincreased when large areas of skin are being formed from a single sheetof metal, consequential upon the aim of eliminating needless joints inthe skin.

It is an object of the invention toenable a sheet forming the skin ofsuch a structure to be lofted after it has been brought to the desiredcurvature, simple or compound, or indeed after it has been brought toany shape lying in more than one plane, such shape being that whichitwill eventually possess after it has been assembled to its supportingmembers such as ribs and spars. Such lofting will eliminate allinaccuracies, e. g., due to incorrect development, and will enable theskin to be in exact register with its supporting members as regardsrivet holes and the like. Another object of the invention is theprovision of lofting apparatus in which a sheet or panel may be heldafter it has been brought to its finished curvature or shape, and inwhich it may be lofted while in that finished shape.

The principle underlying this has been called .envelope tooling becauseit is based upon the aerodynamic form or envelope of the aircraft, whichis not only the first thing upon which finality is reached in the designof a new type, but which also has an intrinsic functional importance.Essentially, the method of assembling consists of building the componentsubassemblies from the skin ing a complex structure of sheet material,such as an aircraft wing, comprises bringing the component parts of theskin of the structure to their finished shape, mounting and retainingeach part while in said shape in a lofting apparatus relatively to adatum line, and marking it out relatively to said datum line.Alternatively, instead of the aircraft skin panels being so formed 'andlofted, there may be formed and lofted in a similar manner a sheet whichis subsequently drilled or otherwise adapted to constitute ajig-template for drilling and assembly of the skin and its associatedparts therein.

Lofting apparatus according to the present invention comprisessupporting and clamping means for a shaped sheet, a datum beamadjustable relatively to the sheet when it is supported andclamped, atowerslidable on the datum beam and movable relatively thereto about twoaxes at right-angles to one another, and scribing means adjustablerelatively to the tower.

The datum beam may be mounted on a wheeled carriage and provided withmeans for vertical adjustment.

The tower may be mounted on a turntable on a slidable carriage on thebeam, the turntable being rotatable about an axis normal to that of thebeam. The tower may be rotatable through 90 about an axis transverse tothat of the beam.

Preferably there are provided vernier adjusting means associated withthe means providing angular movement of the tower relatively to thebeam.

The invention also includes a method of assembling a complex structureof sheet material, such as an aircraft wing, which comprises forming atleast one contour plate, marking it out with a lofting apparatus,converting the marked-out contour plate into a jig-template, e. g., bydrilling, locating a skin component and its associated internal membersin the jig-template, drilling the skin component through thejig-template, and riveting the skin component and associated internalmembers together while they are still located against the jig-template.

The contour-plate may be drilled with holes of equal size, and the skincomponent may be subsequently drilled and countersunk by a drill ofanyrequired size located snugly in the bore of a tube the outsidediameter of which corresponds with the size of holes in thejig-template.

The invention will be described with reference to the accompanyingdrawings, in which:

Figure 1 is a perspective view of a lofting apparatus,

Figure 2 is a front elevation of the datum and supporting beams andcarriage of the apparatus, N

Figure 3 is an end elevation of the beams and carriage, viewed in thedirection of the arrow III, Figure 2,

Figure 4 is an end elevation of the beams and carriage, viewed in thedirection of the arrow IV, Figure 2,

Figure 5 is a fragmentary-perspective view, on a larger scale, of thetower,

Figure 6 is a fragmentary perspective view, on a still larger scale, ofthe base of the tower, showing the turntable partly broken away,

Figure 7 is a perspective view showing the tower supported in aninclined position,

Figure 8 is a perspective view showing the tower in another inclinedposition,

Figure 9 shows marking instruments for use with the apparatus,

Figure 10 is a diagrammatic illustration of a press for forming a metalcomponent, i

V Figure 11 is a corresponding illustration showing the component beingformed,

Figure 12 is a fragmentary perspective view of a simple jig-template,

Figure 13 is a perspective view of another jig-template,

Figure 14 is a view of the jig-template with component parts assembledtherein,

Figure 15 is a diagrammatic view showing drilling of a metal sheetthrough a jig-template, and

Figure 16 is a similar view showing riveting of the sheet throughthe:jigrtemplate.

Referring to the drawings, one form of letting apparatus-for uset'in.thetnanufacture of aircraftwings has a horizontal supporting beam 20 onwhich-the skin 21 to be lofted isstood on edge. The beam-0 hasvertically extending members22 each witha curved edge corresponding withthe: curvature of the skin 21, and-at their upper ends the members 22have clamping means 23, so that the skin 21 maybe supportedrigidly ononeedge in a. substantially vertical plane on the supporting beam 20. Atone end the supporting beam-'20 :has a transverse support 24provided'with two feet 25,and at: the other end alongitudinal support'26-with -a foot-'27, so providing three-pointlsupport. .A datumbeamcornprises a hollow fiat-topped beam '28 mounted: on :a wheeledcarriage 29 on springmountingszlifl, with-provision 31 for verticaladjustment. for levelling. purposes. The datum beam :28 is accuratelymachined, and its fiat"top 32i is arrangedto serve as a surface platealong 'whichmay travel a slidable carriage 33 formed with fingers'34-:engaging:inlongitudinal locating..grooves35'in the top a'nd sidesof the datum beam .28, andhavinga' clamp-36 engaging the beam 28,whereby thewarriage :33 may vbe :maintaine'd inany desired'position..Th'e carriage'33 isin two parts, the upper part 37 being mounted on thelowenpart 38 so as to be-rotatable relativelyithereto:about a verticalaxis through 360 .thus constituting a turntable. The lower part 38 is inthe form ofiahorizontal circular gallery into which a clamping'screw 39idepends from the upper part 37, andthe gallery is provided with anazimuth scale and a Verniermicro setting device. .The upper part 37 maytherefore be accurately set angularlyrelatively to the lowerpart- 38'through a range ofi360i, and clamped in the selected position'by a nut40fon'the screw'39.

The upper part 37 carries a tower 41' pivotally mounted thereon at oneside 'on a horizontalvspindle 42 \vhichis transversely relatively. tothe-datum'beam '28 when the azimuth setting of the turntable is at itszero point. At the other side the "tower has clamps 43=ona rod 44 theends of which pass through a pair of 90 slotted-quadrants 45 carried-bythe upper part 37 of theturntable. The tower 41 may thus-be=locatedand'clamped at any angle between the vertical'andthehorizontal.'A'microsetting device'is providedfor final accuratesetting of theangle.

The tower 41 comprises 'a' braced girder structure:l1avingtwoparallel'sides-ofunequal length,the longer side 46 being that whichmaybe clamped tothe quadrants 45, and the shorter side 47 be'ing"that'Which'is pivotally mounted on the'turntable37. 'lhefree-ends'of thesetwo sides-are joinedby diagonalistruts. The longer side- 46 of thetower-has accuratelymachined'raised edges '48, and when thetoWeris-sePat'Zero, is'atright-angles to the surface 32 of the datum beam28both inplan and elevation.

For use in'setting the tower-longitudinally there isprovided a rule 51fitted with location pins (not shown) and arranged to be movable to 'otherpositions along the datum beam 28. This rule'may also'be used'withthe vertical rule, as indicated'at "51 in Figure 9. For cooperation withthe rule 51 a graticule52 ism'ounted in the lower member 33 of thesliding carriage, an'd'is pro vided with a hair-line (not shown) locatedso astobe-in line with the edges 'lS of thetower'when the tower-is'setat 90 to the datum beam 28, with the edges asqym in a planetransverseofthe datum beam. A second graticulc 53 is employed in a similar way inconjunction "with-the rule '51 when the tower is rotated through 90about a vertical axis so that the edges 48 lie in a vertical planeparallel with the longitudinal axis of the datum beam 28. Fine settingof the position of the towerin the longitudinal direction is efiected,in conjunction with one -or other of the graticules, by means of athreaded shaft 54 rotatable 'by'a"wheel55 in a correspondingly threadedaperture in the bracket 34 'which carries the fingers 34. Clamping ofthe tower after setting in the desired longitudinal position is effectedby the clamp 36. This clamping is efiected along a 45 axis, so forcingstuds 56 hard against the-side of the datum beam 28. For fine adjustmentof the angular position of the tower about the axis of the transverserod 42, the quadrants 45 are mounted at their l'owerends eccentricallyon a transverse bar57 carried in lugs 58 dependant from the upper part-37 of the-turntable. The transverse bar 57 has a tommy bar 57 whereby itmay be rotated and so move the quadrants 45 to'give a very small angularmovement to the tower about the rod42. Clamps 59 are provided to'elamthe tower after such a setting has been given. I

After the skin 21 has been located and clamped on the supporting beam20, the datum beam 28 is moved into position along-side, and is adjustedto a datum line. Iii the caseefaskinfor ana'irc'raft wing;an"advantage'ous datuinlirie' 'is'the 'line indicating the positionof'the' main spar, butafiy other suitable datum may be adopted. For thispurpose the datum beam 28 is providedwith'a fixed spaein twck 49and"a'movable spacing block 50. The movable spacing'block is 'arrangedtobe'loeated" for a jig'base'ofl2 ft.,"9"ft., 'or 7 'ft., but any otherdesired base inay'be'allo'wed for. Each'of the spacing'bloc'ks has alocatingi'pegfiu, which projects through' the block and, whenthe'carriage29 is' moved up to thesupportin'g beam 20, rests on the topsurface of the supporting beam, so -ensuring'that"the"top faces of thesupporting b'eam'20 and datumbea'in"28 "are at the same level.'Attltes'ame time locating pins '61 are passed through lugsonthespacing'blocks '49, '50 andpick up holes in the 'sidefoftliesupportin beams 20. The'two beams are thenbolted together b'ybolts 62.The tower may now be unclatnpe'd an'd slidalong'thedatum beam 28' to anydesired location, and 'there're-cla'mped after being accurately set. Theedges 48 of the tower, which themselvesconstituteasurfaceplatefmay'now'be brought to any desired position, bysetting the "tower in elevation about its horizontal pivotalspiridle42"andif"necessary in azimuthabout the turntable s'pin'dle,micro-setting being possible in each case.

When" the tower-istobe set 'at, say, 70 to'the'vertical,it*isconvenie'nt, toavoi'd undue strain'on the clamping means,to' employ"as a support for its free'eri'd'ave'rtically adjustablejack63"which'rnay be'stoo'd on the top'surfac'e of the datum beam 28 formost positions of the tower. When, however, the free end of the towerextends beyond the datum"b'e'am, either sidewise or endwise, the jack-63 may itself'bes'upported on a trip'od trestle'64,'verticaladjustment'to 'th'eh'e'ight of the free end of the tower being providedby-the jack'63 itself.

'Whenthetower h'asbe'en set ashereinbeforedescribed, ntarlt'ingoutrnaybeaccomplished by a-loose 's'criber 65 heldby'handpre'ssure against theedges'48 o'fthe tower. Linesmay thus b'escribed on the curved'surface'of the skin 21'a'ccurately and without difficulty. In addition,there are "provided a vertical rule 66 arranged to 'be clamped'normal'to'the'datum beam 28 in any desired locationby'a'cl'amp '67, and scribingblocks 68,69 for use inscribing'lines in'planesparallel withadatu'msurface. A scribing block for use with the top 'sur'faceof the'datum b'e'a'm 28may be rested on the beam, as shown in Figures 1 'an'd9,"while a scribing block-for use with the tower may be clamped thereonagainst the'edges 48, as-show'n in Figures'7 and 8, so that thepost ofthe scribing block -is normal to-said side.

Instead est a skin for a wing, there may be mounted on thesupportingbeam 28 a backingrplateioraijig. This is first-curved to the-requiredcurvature of the skin,;and is then marked-out and drilled in the sameway. It is subsequently used as a jig-template for manufacture of thewing, being supported by external ribs and constituting part of 'what'isviitually a female mould. In'as'sembling the ring within such ajig-template, the curved but undrilled skin panels are first located onits inner surface, to which they are attached by clamping pins. Theinternal members such as spars and ribs are then set up in position andsimilarly located and clamped. Drilling is then performed, using thebacking plate as a template. Preferably drilling and countersinking forrivet heads is performed at a single operation. Exact location of theholes can thus be easily transferred from the curved backing plate tothe already curved skin. The method of drilling and riveting will beunderstood by reference to Figures 13 to 16. In Figure 13 the curved andlofted jigtemplate 70 is shown drilled, as at 71, and mounted inexternal ribs 72 against a Wall 73. All the holes 71 are the same size,irrespective of the sizes of rivets eventually to be employed. Thecurved skin 74 is then located in and against the jig-template 70, asshown in Figure 14, and internal ribs 75 and a bulkhead 76 are locatedand clamped in position. Drilling is then performed as shown in Figure15. Into the aperture 71 in the jig-template 70 and from the outside ofthe jig-template there is introduced a sleeve 77 which fits snugly inthe aperture. Within the sleeve 77 is a drill-shank 78 formed at itsoperative end with a drill 79 and a countersink 80. The skin 74 and rib75 are thus drilled to the requisite dimension simultaneously, and theouter surface of the skin 74 is also countersunk in the same operation.When the drilling tool has been withdrawn a rivet having a preformedhead is inserted from the outside of the jigtemplate 70 and the head isheld up on the outside by a tool 81 as shown in Figure 16, while a gun(not shown) is applied to the shank of the rivet from the inside,deforming it as indicated at 82. This method has the advantage that theriveting tends to push the skin 74 into the jig-template 70 and soassists in attaining the correct external form of the finishedstructure.

The depth of countersink is so arranged that the rivet head protrudesfive to ten thousands of an inch from the outer surface of the skin 74after riveting. The rivet heads are then faced ofi, using a smallmilling cutter, instead of the drilling tool, within the sleeve 77.Depth of cut is controlled to prevent damage to the skin surface.

Components that include detachable parts such as doors can be assembledfrom routed skin panels that are already finished to size. Production isthereby speeded up, as the necessity of trimming the detachable part tosize is obviated.

Shallow ctnvatures, whether simple or compound, may be imparted to theskin panels thereby forcing them into the jig-template, which is alreadycurved to the required shape. More severe curvatures must, however, beimparted to the skin panels prior to their location in the jig-template,by normal methods such as wheeling.

Referring to Figures to 12, the leading edge section and similarlyre-curved sections can be made from a flat metal sheet 83 by laying thesheet on a thick sheet of rubber 84 which bridges the open side 85 of achannelshaped structure 86. A punch 87 having a body of laminated paperimpregnated with a synthetic resin and a nose 88 of laminated fabricimpregnated with synthetic resin, and shaped to the conformation of theleading edge section, is then forced against the metal sheet 83 and intothe channel-shaped structure 86, so that the rubber 84 presses the metalplate 83 tightly against the punch 87. The shaped metal sheet 83 is thenremoved from the press and located against the drilled backing plate 89of a jig, or against an extension thereof, for drilling and riveting tothe skin as hereinbefore described.

We claim:

1. Lofting apparatus comprising supporting and clamping means for ashaped sheet, said supporting means comprising a beam having three feet,a datum beam, a wheeled carriage supporting said datum beam, means formoving said datum beam vertically, locking means for fastening saiddatum beam to said supporting means, a tower, means slidably mountingsaid tower on the datum beam whereby the tower is movable relativelythereto about two axes at right angles to one another, and scribingmeans adjustable relatively to said tower, said tower providing guidemeans for said scribing means whereby the wheeled carriage may be movedclosely adjacent the supporting means and data may be inscribed in theshaped sheet by said scribing means.

2. Lofting apparatus comprising, in combination, a supporting beam,clamping means mounted on said beam for retaining a shaped sheet, awheeled carriage, a datum beam mounted on said wheeled carriage,adjustable means for positioning the datum beam at a predeterminedheight relative to said supporting beam, blocks for securing said beamstogether in spaced relation, a turntable slidable on the datum beam, atower mounted on said turntable for movement about two axes at rightangles to one another, and scribing means adjustable relatively to saidtower, said tower providing guide means for said scribing means wherebydata may be inscribed on the shaped sheet by the last named means.

3. Lofting apparatus comprising supporting and clamping means for ashaped sheet, a datum beam, means serving to adjust said datum beamrelatively to said sheet when it is supported and clamped, a turntableslidably mounted on said datum beam, a tower having a polygonal basewith one edge thereof pivoted to said turntable, quadrants pivotallymounted on said turntable, the opposite edge of the base of the towerbeing slidably mounted in slots in said quadrants, means for lockingsaid tower in any selected angular position, and scribing meansassociated with said tower for marking a shaped sheet retained on saidsupporting means, said tower providing guide means for said scribingmeans during the sheet marking operation.

4. Lofting apparatus as claimed .in claim 3 including an adjustable jackfor supporting the outer end of said tower when the tower is supportedat a small acute angle relative to said datum beam.

5. Lofting apparatus for retaining and marking out a shaped structure ofsheet material such as an airplane wing comprising, in combination, abeam supported on three feet for stability, clamping means on said beamfor mounting and retaining the shaped structure, a wheeled carriage, adatum beam, means mounting said datum beam on said wheeled carriage forvertical adjustment with respect thereto, blocks for locking said datumbeam in spaced relation to said first named beam, the position of one ofsaid blocks being adjustable longitudinally of said datum beam, a towerslidable on the datum beam and movable relatively thereto about two axesat right angles to one another, and scribing means associated with saidtower for marking the shaped structure at predetermined points, saidtower providing guide means for said scribing means during the markingoperation.

References Cited in the file of this patent UNITED STATES PATENTS1,043,322 Kountz Mar. 5, 1912 1,540,462 Destombes June 2, 1925 2,095,059Donnelly, Ir. Oct. 5, 1937 2,359,018 Balk Sept. 26, 1944 2,504,961Braaten Apr. 25, 1950 2,519,942 Tedrick Aug. 22, 1950

